Small form factor transmitting device

ABSTRACT

A packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S.application Ser. No. 16/160,817 filed Oct. 15, 2018, which is acontinuation of and claims priority to U.S. application Ser. No.15/855,927 filed Dec. 27, 2017, now issued as U.S. Pat. No. 10,141,717on Nov. 27, 2018, which is a continuation of and claims priority to U.S.application Ser. No. 15/372,524 filed Dec. 8, 2016, now issued as a U.S.Pat. No. 9,887,516 on Feb. 6, 2018, which is a continuation and claimspriority to U.S. application Ser. No. 14/745,316, filed Jun. 19, 2015and now is issued as U.S. Pat. No. 9,548,817 on Jan. 17, 2017, commonlyassigned and incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

The present disclosure is related to an optical transmitting device.More particularly, the present invention provides an improved 1550 nmDFB laser diode package on a submount sharing the cold side of abuilt-in thermoelectric cooling module with an assembly of an asphericaloptical coupling lens. Processes for assembling the optical transmittingdevice are also disclosed.

As science and technology are updated rapidly, processing speed andcapacity of the computer increase correspondingly. The communicationtransmission or reception using the traditional cable is limited tobandwidth and transmission speed of the traditional cable and massinformation transmission required in modern life causes the traditionalcommunication transmission overload. To correspond to such requirement,the optical fiber transmission system replaces the traditionalcommunication transmission system gradually. The optical fibertransmission system does not have similar bandwidth limitations, andalso has advantages of higher speed transmission, longer transmissiondistance, its material is not susceptible to the electromagneticinterference. Therefore, present electronic industry performs researchin optical fiber transmission which will become the mainstream in thefuture. Said optical communication is a technology in that lightfunctions as signal carrier and is transmitted between two nodes via theoptical fiber. Field of the optical communication can be divided intooptical communication side and electrical communication side accordingto the transmission medium. By the optical transceiver, the receivedoptical signal can be converted to an electrical signal capable of beingprocessed by an IC, or the processed electrical signal can be convertedto the optical signal to be transmitted via optical fiber. Therefore,objective of communication can be achieved.

Wavelength-division multiplexing (WDM) is a multitask technology ofprocessing multiple optical carrier signals transmitted by the opticalfiber, and this technology is applied on the different wavelengths oflaser optical signal. Besides, the term “wavelength-divisionmultiplexing” is mostly applied in optical carrier, andfrequency-division multiplexing is applied in radio carrier. Moreover,both of wavelength and frequency are in reciprocal relationship, sotheir concept can be applied to each other.

Wavelength-division multiplexing is implemented by dividing the datachannel into multiple wavelengths in the optical fiber to enable massdata transmission in one optical fiber. The complete wavelength-divisionmultiplexing (WDM) system can be implemented by a wavelength divisionmultiplexer at transmitting end and a wavelength division demultiplexerat receiving end. At present, there are commercial wavelength divisionmultiplexer/demultiplexer which can combine/divide 80 or more channelsin the optical fiber communication system, so that the data transmissionspeed can exceed multiple Tb/s effectively.

In the transmitting module adapted for WDM technology, the connectorusually has single light transmitter structure. However, such lighttransmitter structure can emit optical signal with preset frequencywhich usually lacks stability and often drifts away from the presetwavelength during environmental temperature changes. Although addingthermoelectric cooler module to the transmitting device is known, animproved package integrating a thermister, a thermoelectric cooler (TEC)module, and a laser diode (LD) chip on a submount sharing a common codeside of the TEC module with an aspherical optical coupling lens is stillhighly desired for enhancing control of operation temperature,wavelength stability, and LD-to-fiber coupling efficiency of emittedlight especially in 1310 nm or 1550 nm DWDM channels.

BRIEF SUMMARY OF THE INVENTION

The present disclosure is related to an optical transmitting device.More particularly, the present invention provides an improved packageintegrating C-band DFB laser diode, thermoelectric cooler (TEC) module,directly to a submount attached to a cold-side of the TEC moduletogether with an assembly of an aspherical optical coupling lens.Processes for assembling the optical transmitting device are alsodisclosed. In certain embodiments, the invention is applied to multipleoptical transmitting devices configured to be assembled in upside-downfashion with a top housing disposed at bottom on PCB of a transceiverwith QSFP Small Form Factor (SFF) specification for high bandwidthoptical communication, though other applications are possible.

In a specific embodiment, the present invention provides a packagedtransmitter device. The packaged transmitter device includes a basemember comprising a planar part mounted with a thermoelectric coolermodule, a transmitter module, and an optical coupling lens assembly, andan assembling part connected to one side of the planar part. Thepackaged transmitter device further includes a circuit board bended tohave a first end region being disposed on a top surface of the planarpart and a second end region being raised to a higher level. The firstend region includes multiple electrical connection patches respectivelyconnected to the thermoelectric module and the transmitter module. Thesecond end region includes an electrical port for external connection.Additionally, the packaged transmitter device includes a cover memberdisposed to a fixed position over the planar part to at least cover thethermoelectric module, the transmitter module, the optical coupling lensassembly, and the first end region of the circuit board. Furthermore,the packaged transmitter device includes a cylindrical member installedto the assembling part for enclosing an isolator aligned to the opticalcoupling lens assembly along its axial line and connected to an opticalfiber to couple optical signal from the transmitter module to theoptical fiber.

Therefore, the present disclosure has at least following advantages.First, the optical transmitter package structure provide a compacttransmit module that integrates a thermistor chip, a monitor photodiode(MPD) chip, and laser diode (LD) chip on a submount attached to a coldside surface of a thermoelectric cooler module for improving wavelengthstability. Secondly, the package structure further disposes an opticalcoupling lens assembly next to the submount on the same cold sidesurface of a thermoelectric cooler module so that the distance betweenthe LD chip and the coupling lens can be fixed without being affected byenvironmental temperature change. The coupling lens is an asphericallens providing optimal optical coupling of the emitted laser light fromthe LD chip at a small first distance and better efficiency to focusinto an optical core of fiber at a larger second distance. Thissimplifies calibration process in X-Y plane and Z-axis for opticalalignment of the transmitter device with improved coupling efficiency.The transmitter module on the submount and the coupling lens assemblystill can be easily detached so that the lens body can be recycled forreuse when the transmitter module is damaged. Thirdly, the transmitterpackage structure disposes the TEC module in a recessed region of a basemember that is conveniently set to form a thermal contact with a lidmember as a good heat sink. Fourthly, a bended circuit board associatedwith the transmitter device allows the transmitter device to beinstalled in an upside-down fashion when one or more such transmitterdevices are assembled in a QSFP SFF package of a photonic transceiverdevice to facilitate device heat dissipation by utilizing the lid memberas a good heat sink.

The present invention achieves these benefits and others in the contextof known optical package technology. However, a further understanding ofthe nature and advantages of the present invention may be realized byreference to the latter portions of the specification and attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following diagrams are merely examples, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this process andscope of the appended claims.

FIG. 1 is a perspective view of a packaged TEC-TOSA transmitter deviceaccording to the embodiment of the present invention.

FIG. 2 is a perspective view of the TEC-TOSA transmitter device withouta cover member according to the embodiment of the present invention.

FIG. 2A is a perspective view of an assembly of a transmitter modulewith a coupling lens mounted on a TEC module in the TEC-TOSA transmitterdevice of FIG. 2 according to the embodiment of the present invention.

FIG. 3 is an exploded view of the TEC-TOSA transmitter device accordingto the embodiment of the present invention.

FIG. 4 is a top view of the TEC-TOSA laser device according to anembodiment of the present invention.

FIG. 5A is a cross-section view of the TEC-TOSA laser device of FIG. 5along line A-A according to the embodiment of the present invention.

FIG. 5B is a cross-section view of the TEC-TOSA laser device of FIG. 5along line B-B according to the embodiment of the present invention.

FIG. 6A is a perspective top view of a photonic transceiver packagecomprising two TEC-TOSA transmitter devices of FIG. 1 without a lidmember according to an embodiment of the present invention.

FIG. 6B is a perspective top view of a packaged photonic transceiver inQSFP specification according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is related to an optical transmitting device.More particularly, the present invention provides an improved packageintegrating C-band DFB laser diode chip and a built-in thermoelectriccooler (TEC) module directly on a submount sharing a common cold side ofthe TEC module with an assembly of an aspherical optical coupling lens.Processes for assembling the optical transmitting device are alsodisclosed. In certain embodiments, the invention is applied for highbandwidth optical communication, though other applications are possible.

The following description is presented to enable one of ordinary skillin the art to make and use the invention and to incorporate it in thecontext of particular applications. Various modifications, as well as avariety of uses in different applications will be readily apparent tothose skilled in the art, and the general principles defined herein maybe applied to a wide range of embodiments. Thus, the present inventionis not intended to be limited to the embodiments presented, but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentinvention. However, it will be apparent to one skilled in the art thatthe present invention may be practiced without necessarily being limitedto these specific details. In other instances, well-known structures anddevices are shown in block diagram form, rather than in detail, in orderto avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference. All the featuresdisclosed in this specification, (including any accompanying claims,abstract, and drawings) may be replaced by alternative features servingthe same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Furthermore, any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecific function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. Section 112, Paragraph 6. Inparticular, the use of “step of” or “act of” in the Claims herein is notintended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

Please note, if used, the labels left, right, front, back, top, bottom,forward, reverse, clockwise and counter clockwise have been used forconvenience purposes only and are not intended to imply any particularfixed direction. Instead, they are used to reflect relative locationsand/or directions between various portions of an object.

FIG. 1 is a perspective view of a packaged TEC-TOSA transmitter deviceaccording to the embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, the packagedTEC-TOSA transmitter device 100 includes a TEC base member 111 fordisposing a TEC module, a transmitter module, and an optical couplinglens assembly (not directly visible in FIG. 1) covered by a cover member113 from above. the packaged TEC-TOSA transmitter device 100 alsoincludes a circuit board 114 curved into a “Z” shape having a first endflat region (not visible in this figure) coupled to the TEC base member111 and a second end flat region with multiple electrical conduction pinstripes 1144 substantially leveled with the cover member 113 fortransmitter device's electrical coupling. More details about thosecomponents above will be seen in FIG. 2 below. Additionally, thepackaged TEC-TOSA transmitter device 100 includes a cylindrical member115 having one end being assembled to the TEC base member 111. The TECbase member 111 is made of metal material and can assist thetransmitting module to dissipate heat efficiently. The cylindricalmember 115 is made for packaging optical coupling elements from a laserdiode to an optical fiber. Another end of the cylindrical member 115 isconfigured to be attached with an optical ferrule holder 415 for fixingan optical fiber therein.

FIG. 2 is a perspective view of the TEC-TOSA transmitter device with thecover member removed according to the embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,the TEC-TOSA transmitter device 200 is the same as the TEC-TOSAtransmitter device 100 of FIG. 1 with the cover member 113 beingremoved, revealing some additional elements covered by the cover member113. Now, the TEC base member 111 is substantially visible with a planepart 121, and an assembling part 122 connected at one end the plane part121. The plane part 121 includes a semi-hollow region 125 for holding aTEC module 140 which is sandwiched by a cold side 141 (partially visiblein FIG. 2) and a hot side (not visible in FIG. 2) leveled with bottomsurface of the planar part 121. On part of the cold side 141 of the TECmodule 140, a submount 150 is disposed and fixed using Ag epoxy. Inanother embodiment, the submount 150 is configured to mount atransmitter module 130 including a thermistor chip 1301, a monitorphotodiode (MPD) chip 1302, and a laser diode (LD) chip 1303respectively connected through built-in wire connection in the submount150. Additionally, one end of the Step-shaped circuit board 114 isintegrated with the planar part 121 of the TEC base member 111 andbended to have other end to be leveled at a different height. Thisconfiguration allows an upside-down mounting of the packaged TEC-TOSAtransmitter device on the PCB 420.

Referring further to FIG. 2, the transmitting module 130 comprises athermistor chip 1301, a MPD chip 1302, a LD chip 1303 of DFB or FP typerespectively mounted using either AuSn welding/bonding material or Agepoxy on corresponding locations of the submount 150. The assemblingpart 122 of the TEC base member 111 comprises a vertical portion 123naturally connected to the plane part 121 while configured to allow itsopposite side for assembling additional parts, such as the cylindricalmember 115. An annular through-hole 124 is disposed in the middle of thevertical portion 123 at least above certain level of the cold sidesurface 141 of the TEC module 140. In a specific embodiment, an opticalcoupling lens assembly 160 including a micro glass lens body 1612 heldby a square metal frame 1611 is disposed on the flat cold side surface141 between the submount 150 and the annular through-hole 124,correspondingly to allow the lens body 1612 aligned the LD chip 1303 ofthe transmitting module 312 for coupling emitted laser light throughaxial line of annular through-hole 124 into the cylindrical member 115.The coupling lens assembly 160 is fixed by using epoxy to glue the metalframe 1611 directly onto the cold side surface 141 in front of theannular through-hole 124 with a fixed distance between the LD chip 1303and the lens body 1612. The lens body 1612 comprises an asphericalcurved surfaces on both sides having radius of curvature changesaccording to distance from the optical axis for achieving improved laserlight coupling efficiency.

Referring to FIG. 2 again, the Step-shaped circuit board 114 comprises aboard body 1140 bended in the middle region with an electricalconnection side 1143 disposed on a flat U-shape end 1141 of the boardbody 1140, and an electrical connection port 1144 disposed on a flatstraight end 1142 of the board body 1140, the straight end 1142 isopposite to the U-shape end 1142. As shown, the electrical connectionside 1143 of the board body 1140 is fixed on a top surface of the planarpart 121 of the TEC base member 111 by gluing via a conductive epoxy. Inparticular, the electrical connection side 1143 includes multipleconducting patches that are respectively connected via wire bonding tothe submount 150, thermistor chip 1301, MPD chip 1302, LD chip 1303, andanother submount (not visible) associated with a hot side of the TECmodule 140. The electrical connection port 1144 at the straight end 1142is configured with multiple metallic pin stripes, which are connected tothose conducting patches mentioned above via a pre-printed circuit, forexternal electrical connection. During manufacturing process, afterinstalling the TEC module 140, the submount 150, the transmitter module130, the coupling lens assembly 160, and the Step-shaped circuit board114, the cover member 113 (see FIG. 1) will be placed over the planarpart 121 from above using press fit or epoxy fixing. Then a fillermaterial is properly selected to seal into any open space over thetransmitter module 130 between the cover member 113 and the planar part121 of the TEC base member 111 by infusion or welding, in order toachieve the objective of sealing the transmitter module 130 as well asthe electrical connection side 1143 of the circuit board 114. In anotherembodiment, the Step-shaped circuit board 114 is configured to have theflat straight end 1142 with electrical connection port 1144substantially leveled with an outer surface of the disposed cover member113. In an example of applying the packaged TEC-TOSA transmitter device100 for assembling a small form factor photonic transceiver device, thepackaged transmitter device 100 can be mounted in a upside-down fashionwith the outer surface of the cover member 113 rested on a PCB surfaceof the photonic transceiver device. The electrical connection port 1144is connected directly to corresponding connection spots of the PCB forreceiving control signals for the transmitter module 130 from one ormore control modules mounted on the same PCB.

Additionally shown in FIG. 2, the cylindrical member 115 of the TEC-TOSAtransmitter device 100 is mounted to the assembling part 122 on one endand correspondingly for connecting to a laser output port 415 on anotherend. In this embodiment, the cylindrical member 115 is configured to beproperly adjusted in both X-Y plane, i.e., cross-section planeperpendicular to an axis of the cylindrical member, and Z-space alongthe axis, so as to properly couple the emitted laser light from the LDchip 1303 through the annual through-hole 124 and the cylindrical member115 to an optical fiber (not shown) held by the laser output port 415.

FIG. 2A is a perspective view of an assembly of a transmitter modulewith a coupling lens mounted on a TEC module in the TEC-TOSA transmitterdevice of FIG. 2 according to the embodiment of the present invention.As shown, the transmitter module 130 of FIG. 2 mounted on a submount 150is sharing a same cold side surface 141 of the TEC module 140. The hotside surface 142 is disposed on top of another submount 151 which isattached to the bottom of the semi-hollow region 125 of the planar part121 of the TEC base member 111. Both the hot side surface 142 and thesubmount 151 are not visible in FIG. 2.

FIG. 3 is an exploded view of the TEC-TOSA transmitter device accordingto an embodiment of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, the cylindrical member 115 of TEC-TOSAtransmitter device can be disassembled into a Z-space member 1151 withplane adjusting mechanism, an isolator 1152, a cylindrical receptaclemember 1153 with light distance adjusting mechanism together withoptical fiber connection mechanism, arranged in order from left toright. The isolator 1152 is assembled in an axial location surroundedmainly by the Z-space member 1151 and at least partially by thecylindrical receptacle member 1153. The optical fiber connectionmechanism is configured to connect the cylindrical receptacle member1153 to a laser output port 415 with a fiber ferrule ring to hold anexternal optical fiber (not shown in FIG. 3). The components of thetransmitter module 130 including the thermistor 1301, the MPD chip 1302,and the LD chip 1303 are, each shown with a separate enlarged view,respectively mounted on the submount 150. The submount 150 is placed ona cold side surface 141 of a TEC module 140. The TEC module 140comprises a plurality of single-stage thermoelectric units sandwiched bythe cold site surface 141 and a hot side surface 142. The hot sidesurface 142 is attached with another submount 151 disposed at a bottomof a semi-hollow region 125 recessed into the planar part 121 of the TECbase member 111. Such package structure for the TEC module 140 hasadvantages for efficiently cooling the transmitter module 130 anddissipating heat to the bottom of the TEC base member 111. In a specificembodiment of applying this packaged transmitter device to assembly asmall form factor photonic transceiver, the bottom of the TEC basemember can be conveniently attached directly to a lid member as anefficient heat sink. Also, FIG. 3 shows the Step-shaped circuit board114 having a U-shape end with electrical connection patches to bemounted on top surface 1211 of the planar part 121 of the TEC basemember 111 and a straight end 1142 with electrical pin stripes forexternal electrical connection. A cover member 113 is designed todispose over the planar part 121 next to the vertical portion 123 tocover the transmitter module 130 mounted on the submount 150 on the TECmodule 140 as well as the U-shape end 1141 of the circuit board 114.

FIG. 4 is a top view of the TEC-TOSA transmitter device according to anembodiment of the present invention. FIG. 5A is a cross-section view ofthe TEC-TOSA transmitter device of FIG. 4 along line A-A according tothe embodiment of the present invention. Please refer to FIG. 1 throughFIG. 5A for the illustration of some structural details of the TEC-TOSAtransmitter device 100. As shown in FIG. 3 and FIG. 4, the Z-spacemember 1151 is integrated on the assembling part 122 by welding after aX-Y plane calibration is completed. Any open space between the Z-spacemember 1151 and the assembling part 122 is sealed by infusing filler.For the X-Y plane calibration, the assembling part 122 of the TEC base111 comprises a first connection plane 126 disposed at outer side of thevertical portion 123. The Z-space member 1151 comprises a cylindricalbody 11511 and a second connection plane 11512 disposed at one side ofthe cylindrical body 11511. The second connection plane 11512corresponds to the first connection plane 126. During active alignmentcalibration, a calibration device is used to adjust the relative X-Yplane position between the Z-space member 1151 and the assembling part122 to align Z-axis of the cylindrical body 11511 to the axial line ofthe annular through-hole 124 of the vertical portion 123 of the assemblypart 122 which is previously aligned with the optical coupling lensassembly 160 mounted on the submount 150 on the other side of thevertical portion 122. A calibrated X-Y plane position allows the emittedlaser light from LD chip 1303 to be optimally coupled via the couplinglens assembly 160 to an axial point in the cylindrical body 11511. Asseen below, an isolator 1152 will be disposed at this axial pointsurrounded by the cylindrical body 11511. After the X-Y planecalibration is done, the first connection plane 126 is fixed on thesecond connection plane 11512 by laser spot welding.

FIG. 5B is a cross-section view of the TEC-TOSA laser device of FIG. 7along line B-B according to a specific embodiment of the presentinvention. Referring to both FIG. 3 and FIG. 5B, the cylindricalreceptacle member 1153 with the light distance adjusting mechanism isintegrated onto the Z-space member 1151 and will be fixed by weldingafter a Z-axis coupling calibration is completed, and sealed by infusingfiller material. For the Z-axis calibration, the Z-space member 1151includes a groove track (not visible) disposed at a disposal slot 11513at one side of the cylindrical body 11511 opposing to the secondconnection plane 11512. The disposal slot 11513 is configured forreceiving a coupling portion 11531 of the cylindrical receptacle member1153 which is movable along the as-mentioned groove track. The couplingportion 11531 further includes an inner disposal slot 11533 for holdingthe isolator 1152 fixed by epoxy gluing and press fitting. The couplingportion 11531 additionally includes a recessed outer disposal ring 11532for being hooked by a sleeve body 11534 of the cylindrical receptaclemember 1153. After the Z-axis coupling calibration is completed, thecoupling portion 11531, which holds the isolator 1152, is fixed to theZ-space member 1151 by laser welding or other welding way. The sleevebody 11534 has one end to engage with the recessed outer disposal ring11532 of the coupling portion 11531 and an opposite end to receive anoptical fiber coupling channel 11535 along the axial position. Theoptical fiber coupling channel 11535 is configured to couple with afiber ferrule ring associated with the fiber output port 415 holding theoptical fiber to receive the light emitted from the LD chip 1303,coupled by the coupling lens body 1612, and passed through the isolator1152.

Referring FIG. 3 and FIG. 5B again, the Z-axis coupling calibration isadditionally illustrated. The optical coupling lens body 1612 is anaspherical convex lens having a first convex curve surface facing the LDchip and a second convex curve surface facing the isolator 1152. Bothcurve surfaces are biconvex shaped in general with variable curvaturesdepending on its distance away from the optical axis. The curvatures ofthe first convex curve surface are generally much smaller than those ofthe second convex curve surface. As shown, a distance from the LD chip1303 to (an apex point of) the first convex curve surface of thecoupling lens body 1612 is defined as L1, and a distance from (an apexpoint of) the second convex curve surface of the coupling lens body 1612to the isolator 1152 is defined as L2. Because of the curvaturearrangement mentioned above, L2 should be larger than L1. In thisembodiment, the square metal frame 1611 holding the coupling lens body1612 is disposed directly on the flat cold side surface 141 of the TECmodule 140 in front of the annular through-hole 124 of the assembly part122 for proper coupling with the LD chip 1303 to get maximum opticaloutput before curing the bonding epoxy to fix the distance L1 betweenthe LD chip 1303 and the coupling lens 1612. But the distance L2 fromthe coupling lens body 1612 to the isolator 1152 is adjusted accordingto the light distance adjusting mechanism associated with thecylindrical receptacle member 1153 moving along the groove track of theZ-space member 1151. As L1 is fixed, for better coupling efficiency,length of L2 tends toward a fixed value due to convergencecharacteristic of the coupling lens 1612. Therefore, the length of L2depends on the length of L1. For biconvex aspherical lens, suchconfiguration may increase the tolerance between the cylindricalreceptacle member 1153 and the Z-space member 1151 since L2>L1, so thatdifficulty in assembling process can be reduced.

Further in a specific embodiment, the isolator 1152 is disposed in amechanical body 11521 (FIG. 5A and FIG. 5B). The isolator body 11521 isinserted into the inner disposal slot 11533 of the coupling portion11531 which is inserted into the disposal slot 11513 of the Z-spacemember 1151 (see FIG. 5B). The isolator 1152 can be also disposed toconnect one side of the external optical fiber, but it is not limitedthereto. The optical fiber connection mechanism associated with thecylindrical receptor member 1153 is formed with the light couplingchannel 11535 disposed along axial direction holding an optical fiberconnected to the isolator 1152. The light coupling channel 11535 isconfigured to be attached with a fiber ferrule ring associated with thelaser output port 415 for holding the optical fiber.

FIG. 6A is a perspective top view of a photonic transceiver comprisingtwo TEC-TOSA transmitter devices of FIG. 1 installed in a partialpackage structure without a lid member according to an embodiment of thepresent invention. This diagram is merely an example, which should notunduly limit the scope of the claims. One of ordinary skill in the artwould recognize many variations, alternatives, and modifications. Asshown, a photonic transceiver 400 includes a pair of TEC-TOSAtransmitter devices 100 (of FIG. 1) disposed side-by-side onto a PCBboard 420 mounted on a base member 620 of a transceiver packagestructure. The base member 620 is configured to couple with two verticalpieces 641 of a side member 640. The two vertical pieces 641 areconnected by a horizontal joint piece 642 leveled with the base member620. At a front end region of the photonic transceiver 400 near thehorizontal joint piece 642 on the base member 620, two optical ports,one being an optical input port 418 and another being an optical outputport 419, are disposed. Each optical port is associated with an opticalconnector, such as typical LC connector or other suitable connectorsused in the industry. Alternatively, a paired multi-fiber push on (MPO)connector can be used for both the input and output ports. The back sideof each optical port is coupled to an optical fiber 411 for internalconnection of the photonic transceiver 400. The PCB 420 can be disposedat a short distance away from the optical input port 418 and output port419 and have its back end 426 configured to form an electrical connectorwith multiple metallic stripes 422.

Referring to FIG. 6A, the pair of TEC-TOSA transmitter devices 100 ismounted on the PCB 220 near the pair of optical ports 418 and 419 at thefront end of the transceiver package structure. In a specificembodiment, each TEC-TOSA transmitter device 100 is mounted in aupside-down fashion with its cover member (113 of FIG. 1) facing down incontact with the PCB 420 while leaving its TEC-base member (111 ofFIG. 1) facing up to be in contact with a lid member (see FIG. 6B below)of the transceiver package structure. In an alternative embodiment, eachTEC-TOSA transmitter device 100 is installed with its laser output port415 orientated in opposite direction of the optical input/output ports418 and 419 so that a fiber 412 out of each laser output port isdirecting towards the back end of the transceiver package structure. Thefibers 411 connected to back ends of the optical ports 418/419 are laidbetween the pair of TEC-TOSA transmitter device 100 to join and bundlewith the fibers 412. Then, both fibers 412 and fibers 411 are coupled toa silicon photonics flip-chip 430 via a fiber-to-silicon attachment 431.The silicon photonics flip-chip 430 is mounted in the middle region ofthe PCB 420.

In a specific embodiment, the silicon photonics chip 430 includes adriver module 434 and a TIA (trans-impedance amplifier) module 435 basedon advanced CMOS or SiGe technologies for processing electrical/opticalsignals associated with the photonic transceiver 400. Furthermore, twoCDR ASIC chips 401 and 402 are mounted on the PCB 420 near the back end426 to control electrical interface for communication with networksystem. Multiple metallic pin stripes 422 are disposed at the back end426 of the PCB 420 for plugging the whole photonic transceiver packageinto a network system.

FIG. 6B is a perspective top view of a packaged photonic transceiver inQSFP specification according to an embodiment of the present invention.This diagram is merely an example, which should not unduly limit thescope of the claims. One of ordinary skill in the art would recognizemany variations, alternatives, and modifications. The handle part hasbeen removed from the package structure. In an embodiment, a lid member610 is disposed to couple with both the side member 640 and the basemember 620 to form the packaged photonic transceiver 600. Specifically,the lid member 610 includes a top piece connected to a pair of partialside pieces to couple with the base member 620 to provide a space volumethat holds the photonic transceiver 400 therein, which is revealed inFIG. 6A, while leaving an opening at a back end of the base member 620to allow the electrical connector of the photonic transceiver 400 forplugging in to communication system. The packaged photonic transceiver600 is compatible with the Quad Small Form-factor Pluggable (QSFP)specification, which is designed for a compact small form factor,hot-pluggable photonic transceiver package used for high speed datacommunications applications. Technically, the small form factorpluggable transceiver allows data rates of 4×10 Gbit/s, 4×28 Gbit/s orhigher.

In yet another specific embodiment, the packaged photonic transceiver600 in this embodiment applies technology of wavelength-divisionmultiplexing (WDM), two or more TEC-TOSA transmitter devices to use aDFB laser diode to generate laser light of different wavelengths at anychannels of dense-wavelength-division-multiplexing spectrum band. Twochannels can further be combined into one single-mode optical fiber viawavelength-division multiplexer for middle distance and long distancetransmission. Next, the received optical signal is performed alight-split process by the demultiplexer and the split optical signalsare introduced to different channels. In this embodiment, except WDMtechnology, the photonic transceiver package 100 also can be applied torelated optical communication technologies, such as binary phase shiftkeying modulation (BPSK), quadrature phase shift keying modulation(QPSK), conventional/coarse wavelength division multiplexing (CWDM),dense wavelength division multiplexing (DWDM), and optical add/dropmultiplexer (OADM), reconfigurable optical add/drop multiplexer (ROADM).

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

What is claimed is:
 1. A method of implementing a photonic transceiverin a network system comprising: packaging a first transmitter device anda second transmitter device separately in a TEC-TOSA package; couplingthe first transmitter device and a second transmitter devicerespectively to a silicon photonics chip and mounting two TEC-TOSApackages respectively for the first transmitter device and a secondtransmitter device side-by-side on a PCB board, the PCB board beingconfigured with a front end for mounting an optical input port and anoptical output port respectively connected to the silicon photonics chipvia optical fibers and a back end for forming multiple metallic stripesconfigured as an electrical connector; plugging the electrical connectorto the network system; and connecting a pair of external optical fibersrespectively to the optical input port and the optical output port forrespectively providing incoming optical signals and outgoing opticalsignals.
 2. The method of claim 1 wherein packaging the firsttransmitter device comprises: providing a base member comprising aplanar part extended to an assembling part; mounting a thermoelectriccooler module, a transmitting module, and an optical coupling lensassembly on a top surface of the planar part; disposing a circuit boardbended in step-shape with a first end region sitting on a top surface ofthe planar part and a second end region being a raised level, the firstend region comprising multiple electrical connection patchesrespectively connected to the thermoelectric module and the transmittingmodule, the second end region comprising an electrical port for externalconnection; disposing a cover member to a fixed position over the planarpart to at least cover the thermoelectric module, the transmittingmodule, the optical coupling lens assembly, and the first end region ofthe circuit board; assembling a cylindrical member to the assemblingpart, the cylindrical member enclosing an isolator aligned to theoptical coupling lens assembly along its axial line and connected to afirst optical fiber to output optical signal from the transmittingmodule; and mounting the base member on the PCB board.
 3. The method ofclaim 2 wherein the mounting the thermoelectric cooler module comprises:disposing a plurality of single-stage thermoelectric units sandwichedbetween a hot side surface and a cold side surface; attaching the hotside surface to a first submount inside a semi-hollow region recessedfrom the top surface of the planar part; and attaching the cold sidesurface partially with a second submount.
 4. The method of claim 3wherein mounting the transmitting module comprises mounting a thermistorchip, a monitor photodiode chip, and a laser diode chip respectively onthe second submount.
 5. The photonic transceiver of claim 3 whereinmounting the optical coupling lens assembly comprises: holding anaspherical lens with a square metal frame; and directly mounting thesquare metal frame that holds the aspherical lens on the cold sidesurface between the second submount and the assembly part.
 6. The methodof claim 2 wherein the assembly part comprises a vertical portionattached to a side of the planar part above the top surface, thevertical portion having a connection plane distal to the planar part andan annular through-hole positioned near a center position of thevertical portion to allow the emitted light from the transmitting modulecoupled via the optical coupling lens assembly to pass into thecylindrical member.
 7. The method of claim 6 wherein assembling acylindrical member comprises: attaching a first cylindrical body with aplane adjusting mechanism to the connection plane; and attaching one endof a second cylindrical body with a light distance adjusting mechanismto the first cylindrical body while leaving another end of the secondcylindrical body with an optical fiber connection mechanism forconnecting a fiber.
 8. The method of claim 7 wherein assembling acylindrical member further comprises: fixing the isolator to a couplingportion of the second cylindrical body; enclosing the isolator in adisposal slot of the first cylindrical body; using the plane adjustingmechanism to adjust the first cylindrical body against the connectionplane to calibrate X-Y plane positions relative to the light out of theoptical coupling lens assembly; and using the light distance adjustingmechanism to adjust the second cylindrical body against the firstcylindrical body to calibrate a Z-axis position from the opticalcoupling lens assembly.
 9. The method of claim 8 wherein assembling acylindrical member further comprises engaging one end of a sleeve bodyto an outer disposal ring of the coupling portion; and using another endof the sleeve body to receive an optical fiber coupling channel forholding the first optical fiber.
 10. The method of claim 2 whereindisposing the circuit board comprises configuring a middle region incertain angles respectively connected to both the first end region beingflat on the top surface of the planar part and the second end regionbeing flat at the raised level substantially in parallel with the firstend region, the second end region being extended outside of the covermember and the base member.
 11. The method of claim 10 wherein the firstend region comprises a U-shape end to hold the multiple electricalconnection patches.
 12. The method of claim 5 wherein holding theaspherical lens comprises configuring the aspherical lens with a firstconvex curve surface having a first plurality of curvatures at differentsurface locations relative to its central axis and a second convex curvesurface having a second plurality of curvatures at different surfacelocations relative to its central axis, each of the first plurality ofcurvatures being smaller than each of the second plurality ofcurvatures.
 13. The method of claim 12 wherein holding the asphericallens further comprises disposing a first apex point of the first convexcurve surface at a first distance away from the laser diode chip and asecond apex point of the second convex curve surface at a seconddistance away from the isolator.
 14. The method of claim 13 wherein thefirst distance is fixed at 0.25 mm with 0.8 mm tolerance and the seconddistance is adjustable within a range from 1.5 mm to 4.0 mm forachieving a coupling efficiency of at least 50%.
 15. The method of claim2 wherein coupling the first transmitter device to the silicon photonicschip further comprises: coupling the transmitting module on the siliconphotonics chip via the first optical fiber and with inner terminals ofthe optical input port and the optical output port respectively via asecond optical fiber and a third optical fiber; and mounting a fiberholder on the PCB board, wherein the fiber holder holds at least thefirst, second, and third optical fibers.
 16. The method of claim 15further comprising providing a case having a base piece, a side piecewith two vertical parts connected by a horizontal joint part, and a lidpiece with a top part connected to a pair of partial-side parts; whereinthe base piece is configured to couple with the two vertical parts ofthe side piece and the horizontal joint part leveled with the basepiece, the lid piece is configured to couple with the base piece withthe pair of partial-side parts joined with the two vertical parts. 17.The method of claim 16 wherein the case further comprises dimensions andshapes compatible with Quad Small Form-factor Pluggable specification.18. The method of claim 15 wherein the silicon photonics chip comprisesa photonics substrate holding a driver module, a trans-impedanceamplifier module, and a fiber-to-silicon attachment for coupling thefirst, second, and the third optical fibers to the photonics substrate.19. The method of claim 15 wherein coupling the transmitting modulefurther comprises laying the first fiber out of the transmitting moduletoward the second end of the PCB board.
 20. The method of claim 2,further comprising: adding a second transmitter device on the PCB board,the second transmitter device being packaged substantially same as thefirst transmitting device and including a fourth optical fiber coupledto the silicon photonics chip for providing a second wavelength channelof the photonic transceiver; and disposing the PCB board into the case.